Most firearms utilize a bolt with a planar face that is designed to mate with a corresponding planar face of a breech or firing chamber (e.g., to seal a cartridge in the chamber for firing). It is understood however, that a tapered or cone-shaped mating configuration is advantageous. Tapering the face of the bolt and providing a cone-shaped breech, for example, provides a less obstructive path for feeding cartridges into the firing chamber and/or provides for an increased surface contact mating area between the bolt and the breech. These advantages allow for (i) more reliable cartridge feeding (e.g., less jamming and/or cartridge damage upon feeding) and (ii) increased contact area provides an enhanced seal that is less likely to result in blowback or structural failure, respectively.
Different types and/or styles of cartridge ejection mechanisms or “ejectors” are utilized in various types of firearms. Some are integral to the firearm bolt (e.g., a “plunger-style” ejector) while others are integral to the receiver assembly. While each available style provides differing benefits and drawbacks, many prefer the simplicity and bolt-integral nature and operating characteristics of the plunger-style ejector.
Despite these recognized advantages, most firearms do not utilize a cone-shaped breech. This is primarily due to the fact that tapered bolt configurations capable of use in cone-shaped breech systems are not capable of functioning properly in repeating firearms, particularly in conjunction with a plunger-style ejector. In other words, magazine and clip-feed firearms that are designed to store and repeatedly load, fire, and eject cartridges in a repeating fashion are unable to benefit from the advantages of a cone-breech design, especially when combined with a plunger-style ejector, due to interference with cartridge loading.